Portable electronic devices, such as smartphones and tablets are in wide usage in the world today. These portable electronic devices increasingly utilize touch screens to receive input from users, and are employed for many tasks that were previously performed using desktop computers. Due to the touch screen serving as the input device, as well as due to the increased functions for which such portable electronic devices are used, there is a market demand for such devices to have larger screens.
In addition to the market demand for large touch screens, there is also an increasing market demand for such large touch screens to be operable via a stylus. While a typical capacitive touch screen can be operated via a passive stylus without modification, data such as pressure, whether a switch on the stylus has been pressed, and data from an accelerometer or gyroscope in the active stylus, is unable to be sent. In addition, it may be difficult to differentiate a touch from a passive stylus and an user's hand, but such differentiation is achievable with a high degree of accuracy when an active stylus is used instead.
An active stylus contains circuitry that generates and transmits signals that can be picked up by a digitizer of the electronic device. These signals can be used to determine the location of the active stylus with respect to the screen (even if the active stylus is not in contact with the screen, and with a much greater degree of accuracy than a passive stylus), as well as the pressure with which the active stylus is being pressed against the touch screen.
An active stylus paired with a digitizer in electronic device is therefore able to provide the desired degree of accuracy, as well as additional functionality mentioned above such as pressure sensing. Thus, there is a demand for large touch screen electronic devices with active styluses.
The driving of such large touch screens capable of operation with such active styluses, however, presents challenges. Therefore, further advances are needed in this area.